The hardiness zone system is a crude method of showing if a plant is suitable for your area. It is an American invention and works reasonably well for a country with a dry, continental climate. The UK has a maritime climate which has to factor in wetness. A hardiness zone just looks at the minimum temperature range for the plant to survive so does have some value to us but should not be taken as a guarantee that a plant will survive.
For the UK, look at this site: http://www.uk.gardenweb.com/forums/zones/hze1.html
It indicates that plants will survive above minimum temperatures of -7 to -12C, or zone 8. According to the label your plant should just about survive.

That reply is very interesting Bulbaholic. I had been too lazy to study when I came across it anywhere - I just did my Ostrich bit!! Now at least I can apply a bit of thought to it. Thank you.

Thank you for that. Just about survive :) That will do for me.